ORA-27090: Unable to reserve kernel resources for asynchronous disk I/O

User may receive below error when connecting to Database, I have encountered this issue in various versions of Oracle such as 10g, 11g, 12c and 19c.

ERROR:
ORA-01017: invalid username/password; logon denied
ORA-27090: Unable to reserve kernel resources for asynchronous disk I/O
Linux-x86_64 Error: 2: No such file or directory
Additional information: 3
Additional information: 128
Additional information: 2022083592

You may see below messages in alert.log

ORA-27090: Message 27090 not found; product=RDBMS; facility=ORA
Additional information: 3
Additional information: 128
Additional information: 65536
OR

ORA-27090: UNABLE TO RESERVE KERNEL RESOURCES FOR ASYNCHRONOUS DISK I/O
Additional information: 3
Additional information: 128
Additional information: 65536
OR

ORA-27090: Message 27090 not found; product=RDBMS; facility=ORA
Linux-x86_64 Error: 4: Interrupted system call
Additional information: 3
Additional information: 128
Additional information: 65536

DBWR trace
io_setup(4096, 0x66e1588) = -1 EAGAIN (Resource temporarily unavailable),

You will see above error when "aio-max-nr" kernel limit is too low.

Increasing the "aio-max-nr" kernel limit as per the Oracle recommendation. I have set the value as
fs.aio-max-nr= 3145728 in my environment.

Thanks

Satishbabu Gunukula, Oracle ACE

http://oracleracexpert.com